1. Field of the Invention
The present invention relates to a process for the production of high temperature-resistant metallic components having finely porous walls, and particularly such through which a cooling medium can diffuse.
For thin-walled high temperature components such as, for example, combustion chambers or the turbine blades of gas turbines which are to be cooled with the end of a through-passing cooling medium pursuant to the effusion principle, it is desirable to provide finely porous, thin metal walls. Effusion cooling is a particularly effective type of cooling which, for instance when applied to combustion chambers, will afford the advantage that the cooling medium will take part in the combustion process whereby it is possible to contemplate advantages through uniform combustion (for example, improved combustion, as a result a lower fissure formation and a lower proportion of NO.sub.x in the exhaust gas).
2. Discussion of the Prior Art
Heretofore, wire meshes and metal feltings have been utilized for effusion-cooled, thin-walled high temperature components which, however, evidence an inadequate high-temperature stability or strength and oxidation resistance in a temperature range of 1000.degree. C. and higher. Moreover, the shaping of such materials is difficult and substantive connections (for instance, through welding or soldering) are only possible to an insufficient extend due to the apparent notching effect and adverse influence on the material matrix. Also in the field of producing turbine blades it has not been possible until the present to be able to fasten high-temperature resistant porous layers as a blade sheathing upon a supporting core.
The most recent investigations have now indicated that it is possible, with the aid of oriented eutectic solidification, to produce extremely finely porous filter membranes with through porosity, in which thin discs are separated from a rod of oriented eutectically solidified material transversely to the fiber orientation, and whereupon the fibers of the one material are then etched out.